Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash)can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization.In this paper,the physicochemical pr...Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash)can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization.In this paper,the physicochemical properties of coal gangue and coal fly ash are introduced.The mechanism and application characteristics of the pretreatment processes for zeolite synthesis from coal-based solid wastes are also introduced.The synthesis processes of coal-based solid waste zeolite and their advantages and disadvantages are summarized.Furthermore,the application characteristics of various coal-based solid waste zeolites and their common application fields are illustrated.Finally,we propose an alkaline fusion-assisted supercritical hydrothermal crystallization as an efficient method for synthesizing coal-based solid waste zeolites.In addition,more attention should be given to the recycling of alkaline waste liquid and the application of coal-based solid waste zeolites in the field of volatile organic compound adsorption removal.展开更多
Single-atomic site catalysts have drawn considerable attention because of their maximum atom-utilization efficiency and excellent catalytic activity.In this work,a highly active single-atomic Pt site photocatalyst was...Single-atomic site catalysts have drawn considerable attention because of their maximum atom-utilization efficiency and excellent catalytic activity.In this work,a highly active single-atomic Pt site photocatalyst was synthesized through employing defective Ti0_(2) nanosheets as solid support for photo-catalytic water splitting.It indicated that the surface oxygen vacancies on defective Ti0_(2) nanosheets could effectively stabilize the single-atomic Pt sites through constructing a three-center Ti-Pt-Ti structure.The Ti-Pt-Ti structure can hold the stability of isolated single-atomic Pt sites and facilitate the separation and transfer of photoinduced charge carriers,thereby greatly improving the photocatalytic H2 evolution.Notably,our synthesized photocatalyst exhibited a remarkably enhanced H2 evolution performance,and the H2 production rate is up to 13460.7μmol h^(-1)·g^(-1),which is up to around 29.0 and 4.7 times higher than those of Ti0_(2) nanosheets and Pt nanoparticles-Ti0_(2).In addition,a plausible enhanced reaction mechanism was also proposed combining with photo-electrochemical characterizations and density functional theoiy(DFT)calculation results.Ultimately,it is believed that this work highlights the benefits of a single-site catalyst and paves the way to rationally design the highly active and stable single-atomic site photocatalysts on metal oxide support.展开更多
The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this study.The Mn/G/D possessed higher specific surface area,lower electron-hole pairs' ...The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this study.The Mn/G/D possessed higher specific surface area,lower electron-hole pairs' recombination rate,as well as wider and stronger visible light absorption capacity.Since the synergistic effect between g-C_(3 )N_(4) and MnFe_(2) O_(4),the photogene rated electron could transfer from g-C3 N4 to MnFe_(2) O_(4),which could promote the migration of electrons as well as enhance the photocatalytic activity and peroxymonosulfate(PMS) activation efficiency.Mn/G/D-5% composite displayed the excellent degradation performance of bisphenol A(BPA) with the removal efficiency of 99.9% under PMS/Vis system,which was approximately 2.47 and 63.8 times as high as that of the Mn/G/D-5%/PMS and Mn/G/D-5%/Vis system,respectively.Moreover,negative electricity derived from diatomite surface also promoted the photogenerated carriers' migration,and the degradation rate constant was around 2.4 times higher than that of MnFe_(2) O_(4)/g-C_(3) N_(4)(Mn/G).In addition,quenching experiments showed that both radical pathway(h^(+),·OH,·O_(2)^(-)and SO_(4)·^(-)) and non-radical pathway(^(1) O_(2)) were responsible for the degradation of BPA.展开更多
Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-ef...Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-efficient removal of indoor formaldehyde(HCHO).First,the optimal preparation conditions of the two composites were determined,and then their microstructures and morphologies were characterized and analyzed.Batch HCHO adsorption experiments with the two types of amino-modified DE composites were also conducted to compare their adsorption properties.Experimental results indicated that the pseudo-second-order kinetic and Langmuir isotherm models could well describe the adsorption process,and the maximum adsorption capacities of APTS/DE and GLY/DE prepared under optimal conditions at 20°C were 5.83 and 1.14 mg·g^(-1),respectively.The thermodynamic parameters of the composites indicated that the adsorption process was spontaneous and exothermic.The abundant amine groups grafted on the surface of DE were derived from the Schiff base reaction and were essential for the high-efficient adsorption performance toward HCHO.展开更多
A novel Ag/g-C_(3)N_(4)/kaolinite composite photocatalyst was fabricated for the first time through a two-step assembly strategy by employing in situ calcination and a photodeposition process.The synthesized Ag/g-C_(3...A novel Ag/g-C_(3)N_(4)/kaolinite composite photocatalyst was fabricated for the first time through a two-step assembly strategy by employing in situ calcination and a photodeposition process.The synthesized Ag/g-C_(3)N_(4)/kaolinite composite reached a higher degradation rate of ibuprofen(IBP)with a reaction rate constant of 0.0113 min^(-1) at an Ag content of 7% under visible-light irradiation,which was approximately 1.87 times that of the Ag/g-C_(3)N_(4) composite.Based on the physicochemical properties,the enhanced photocatalytic activity was attributed to the stronger adsorption property,wider photoresponse range and more efficient separation and transfer of electron-hole pairs.Furthermore,the incorporation of monodispersed Ag nanoparticles onto the g-C_(3)N_(4)/kaolinite sheets provided more reactive sites for the IBP degradation.In addition,according to the EPR study and trapping experiments,it was demonstrated that holes(h^(+))should be the key reactive species.A possible pathway of IBP degradation was also proposed based on the detected intermediates.Overall,the results of this work may facilitate the design of a novel visible-light-driven photocatalyst with a high efficiency that is derived from a natural mineral for environmental remediation.展开更多
The recent annual output of major industrial mineral powders in the mainland of China has been more than 100 million t, accompanied by active development of such supporting technology as comminution, classification, s...The recent annual output of major industrial mineral powders in the mainland of China has been more than 100 million t, accompanied by active development of such supporting technology as comminution, classification, separation/purification, and surface modification. In particular, the present paper reviews technologies for preparing ultra-fine particles involving dry and wet processing, modification and composition, calcination of kaolin clay, and processing of spherical/acerous industrial minerals.展开更多
Diatomite supported nano zero valent iron(n ZVI)catalyst(NDA)with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribution of NDA can be re...Diatomite supported nano zero valent iron(n ZVI)catalyst(NDA)with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribution of NDA can be regulated and controlled through adjusting the loading amount of n ZVI.In general,the nano three-dimensional network formed by n ZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA,and further formed more active sites,which made NDA have better performance in activating PMS to degrade BPA than pure n ZVI.The pseudo-first-order reaction rate constant of 50-NDA(50%-n ZVI/diatomite)is almost 3 times higher than that of pure n ZVI.Besides,the electron paramagnetic resonance(EPR)and radical quenching experiments showed that the activation process was dominated by the sulfate radical(SO_(4)^(-))and hydroxyl radical(·OH)produced by Fe;oxidation.The generated electrons promote the self-decomposition of PMS to produce singlet oxygen(^(1)O_(2)),and then the valence state of iron changes to produce free radicals.In addition,the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrometer(LC-MS).This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.展开更多
A novel illite@carbon（I@C） nanocomposite adsorbent has been synthesized via a facile hydrothermal carbonization process（HTC） using glucose as carbonaceous source and illite as the carrier.The morphology,microstruc...A novel illite@carbon（I@C） nanocomposite adsorbent has been synthesized via a facile hydrothermal carbonization process（HTC） using glucose as carbonaceous source and illite as the carrier.The morphology,microstructure and surface properties of the prepared nanocomposite adsorbent were analyzed by FESEM,TGA,XRD,FT-IR and Zeta potential measurements.Batch experiments were carried out on the adsorption of Cr（Ⅵ） to determine the adsorption properties of the composite.The adsorption of Cr（Ⅵ） onto the I@C nanocomposite was well described by the pseudo-second-order kinetic model and Langmuir isotherm.Compared with the illite and carbon material（SC） separately,the prepared I@C nanocomposite adsorbent exhibited enhanced adsorption performance for Cr（Ⅵ） with a maximum adsorption capacity of 149.25 mg/g,which was higher than that of most reported adsorbents.In addition,the adsorption process was spontaneous and endothermic based on the adsorption thermodynamics study.The adsorption of Cr（Ⅵ） by I@C was highly p H-dependent and the optimum adsorption occurred at p H 2.0.The Zeta potential analysis results indicated that the electrostatic interactions between anionic Cr（Ⅵ） and the positively charged surface of the adsorbent might be critical to the adsorption mechanism.This study demonstrated that the I@C nanocomposite should be a promising candidate for a low-cost,environmental friendly and highly efficient adsorbent for the removal of toxic Cr（Ⅵ） from wastewater.展开更多
基金This work was financially supported by the National Key R&D Program of China(Nos.2020YFC1806504 and 2019YFC1904903)the Yue Qi Young Scholar Project,China University of Mining&Technology(Beijing)(No.2017QN12).
文摘Zeolite derived from coal-based solid wastes(coal gangue and coal fly ash)can overcome the environmental problems caused by coal-based solid wastes and achieve valuable utilization.In this paper,the physicochemical properties of coal gangue and coal fly ash are introduced.The mechanism and application characteristics of the pretreatment processes for zeolite synthesis from coal-based solid wastes are also introduced.The synthesis processes of coal-based solid waste zeolite and their advantages and disadvantages are summarized.Furthermore,the application characteristics of various coal-based solid waste zeolites and their common application fields are illustrated.Finally,we propose an alkaline fusion-assisted supercritical hydrothermal crystallization as an efficient method for synthesizing coal-based solid waste zeolites.In addition,more attention should be given to the recycling of alkaline waste liquid and the application of coal-based solid waste zeolites in the field of volatile organic compound adsorption removal.
基金This research was funded by the Canadian Centre for Clean Coal/Carbon and Mineral Processing Technologies(C5MPT),the National Key R&D Program of China(2017YFB0310803)and the China Scholarship Council(CSC).We thank the NanoFAB at the University of Alberta for the convenience of instruments use,and the kindly help of Nanqi Duan and Chao Qi on sample characterization.
文摘Single-atomic site catalysts have drawn considerable attention because of their maximum atom-utilization efficiency and excellent catalytic activity.In this work,a highly active single-atomic Pt site photocatalyst was synthesized through employing defective Ti0_(2) nanosheets as solid support for photo-catalytic water splitting.It indicated that the surface oxygen vacancies on defective Ti0_(2) nanosheets could effectively stabilize the single-atomic Pt sites through constructing a three-center Ti-Pt-Ti structure.The Ti-Pt-Ti structure can hold the stability of isolated single-atomic Pt sites and facilitate the separation and transfer of photoinduced charge carriers,thereby greatly improving the photocatalytic H2 evolution.Notably,our synthesized photocatalyst exhibited a remarkably enhanced H2 evolution performance,and the H2 production rate is up to 13460.7μmol h^(-1)·g^(-1),which is up to around 29.0 and 4.7 times higher than those of Ti0_(2) nanosheets and Pt nanoparticles-Ti0_(2).In addition,a plausible enhanced reaction mechanism was also proposed combining with photo-electrochemical characterizations and density functional theoiy(DFT)calculation results.Ultimately,it is believed that this work highlights the benefits of a single-site catalyst and paves the way to rationally design the highly active and stable single-atomic site photocatalysts on metal oxide support.
基金the financial support provided by the Beijing Natural Science Foundation (2202044)the Fok Ying Tung Education Foundation, China (171042)+1 种基金the National Postdoctoral Program for Innovative Talents (BX20190370)the Fundamental Research Funds for the Central Universities (2021JCCXHH04)。
文摘The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this study.The Mn/G/D possessed higher specific surface area,lower electron-hole pairs' recombination rate,as well as wider and stronger visible light absorption capacity.Since the synergistic effect between g-C_(3 )N_(4) and MnFe_(2) O_(4),the photogene rated electron could transfer from g-C3 N4 to MnFe_(2) O_(4),which could promote the migration of electrons as well as enhance the photocatalytic activity and peroxymonosulfate(PMS) activation efficiency.Mn/G/D-5% composite displayed the excellent degradation performance of bisphenol A(BPA) with the removal efficiency of 99.9% under PMS/Vis system,which was approximately 2.47 and 63.8 times as high as that of the Mn/G/D-5%/PMS and Mn/G/D-5%/Vis system,respectively.Moreover,negative electricity derived from diatomite surface also promoted the photogenerated carriers' migration,and the degradation rate constant was around 2.4 times higher than that of MnFe_(2) O_(4)/g-C_(3) N_(4)(Mn/G).In addition,quenching experiments showed that both radical pathway(h^(+),·OH,·O_(2)^(-)and SO_(4)·^(-)) and non-radical pathway(^(1) O_(2)) were responsible for the degradation of BPA.
基金financially supported by the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.C201903678)the Fundamental Research Funds for the Central Universities(2020YJSHH02)+1 种基金Fok Ying Tung Education Foundation,China(No.171042)the Yue Qi Young Scholar Project of the China University of Mining and Technology(Beijing)(No.2017 QN12)。
文摘Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-efficient removal of indoor formaldehyde(HCHO).First,the optimal preparation conditions of the two composites were determined,and then their microstructures and morphologies were characterized and analyzed.Batch HCHO adsorption experiments with the two types of amino-modified DE composites were also conducted to compare their adsorption properties.Experimental results indicated that the pseudo-second-order kinetic and Langmuir isotherm models could well describe the adsorption process,and the maximum adsorption capacities of APTS/DE and GLY/DE prepared under optimal conditions at 20°C were 5.83 and 1.14 mg·g^(-1),respectively.The thermodynamic parameters of the composites indicated that the adsorption process was spontaneous and exothermic.The abundant amine groups grafted on the surface of DE were derived from the Schiff base reaction and were essential for the high-efficient adsorption performance toward HCHO.
基金the financial support provided by the Beijing Natural Science Foundation(2202044)the National Postdoctoral Program for Innovative Talents(BX20190370).
文摘A novel Ag/g-C_(3)N_(4)/kaolinite composite photocatalyst was fabricated for the first time through a two-step assembly strategy by employing in situ calcination and a photodeposition process.The synthesized Ag/g-C_(3)N_(4)/kaolinite composite reached a higher degradation rate of ibuprofen(IBP)with a reaction rate constant of 0.0113 min^(-1) at an Ag content of 7% under visible-light irradiation,which was approximately 1.87 times that of the Ag/g-C_(3)N_(4) composite.Based on the physicochemical properties,the enhanced photocatalytic activity was attributed to the stronger adsorption property,wider photoresponse range and more efficient separation and transfer of electron-hole pairs.Furthermore,the incorporation of monodispersed Ag nanoparticles onto the g-C_(3)N_(4)/kaolinite sheets provided more reactive sites for the IBP degradation.In addition,according to the EPR study and trapping experiments,it was demonstrated that holes(h^(+))should be the key reactive species.A possible pathway of IBP degradation was also proposed based on the detected intermediates.Overall,the results of this work may facilitate the design of a novel visible-light-driven photocatalyst with a high efficiency that is derived from a natural mineral for environmental remediation.
文摘The recent annual output of major industrial mineral powders in the mainland of China has been more than 100 million t, accompanied by active development of such supporting technology as comminution, classification, separation/purification, and surface modification. In particular, the present paper reviews technologies for preparing ultra-fine particles involving dry and wet processing, modification and composition, calcination of kaolin clay, and processing of spherical/acerous industrial minerals.
基金financially supported by the Beijing Natural Science Foundation(No.2202044)the National Postdoctoral Program for Innovative Talents(No.BX20190370)+1 种基金the China Postdoctoral Science Foundation(No.2020M680757)the Fundamental Research Funds for the Central Universities(No.2020YJSHH03)。
文摘Diatomite supported nano zero valent iron(n ZVI)catalyst(NDA)with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribution of NDA can be regulated and controlled through adjusting the loading amount of n ZVI.In general,the nano three-dimensional network formed by n ZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA,and further formed more active sites,which made NDA have better performance in activating PMS to degrade BPA than pure n ZVI.The pseudo-first-order reaction rate constant of 50-NDA(50%-n ZVI/diatomite)is almost 3 times higher than that of pure n ZVI.Besides,the electron paramagnetic resonance(EPR)and radical quenching experiments showed that the activation process was dominated by the sulfate radical(SO_(4)^(-))and hydroxyl radical(·OH)produced by Fe;oxidation.The generated electrons promote the self-decomposition of PMS to produce singlet oxygen(^(1)O_(2)),and then the valence state of iron changes to produce free radicals.In addition,the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrometer(LC-MS).This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.
基金supported by the Fundamental Research Funds for the Central Universities(No.2015QH01)
文摘A novel illite@carbon（I@C） nanocomposite adsorbent has been synthesized via a facile hydrothermal carbonization process（HTC） using glucose as carbonaceous source and illite as the carrier.The morphology,microstructure and surface properties of the prepared nanocomposite adsorbent were analyzed by FESEM,TGA,XRD,FT-IR and Zeta potential measurements.Batch experiments were carried out on the adsorption of Cr（Ⅵ） to determine the adsorption properties of the composite.The adsorption of Cr（Ⅵ） onto the I@C nanocomposite was well described by the pseudo-second-order kinetic model and Langmuir isotherm.Compared with the illite and carbon material（SC） separately,the prepared I@C nanocomposite adsorbent exhibited enhanced adsorption performance for Cr（Ⅵ） with a maximum adsorption capacity of 149.25 mg/g,which was higher than that of most reported adsorbents.In addition,the adsorption process was spontaneous and endothermic based on the adsorption thermodynamics study.The adsorption of Cr（Ⅵ） by I@C was highly p H-dependent and the optimum adsorption occurred at p H 2.0.The Zeta potential analysis results indicated that the electrostatic interactions between anionic Cr（Ⅵ） and the positively charged surface of the adsorbent might be critical to the adsorption mechanism.This study demonstrated that the I@C nanocomposite should be a promising candidate for a low-cost,environmental friendly and highly efficient adsorbent for the removal of toxic Cr（Ⅵ） from wastewater.
